Adjust Digital Out (PO) Voltage

[jliu317]

How can you alter the Digital Out (PO.x) voltage for the NI 6343 (it is a DAQ)? By default it outputs 5V on high.  I need 3.3V output for my application.

[crossrulz]

I recommend getting a buffer that can do the voltage changeover.  Of course, you will need to supply a 5V and 3.3V to power the buffer, but that is the best way to go.

Another method I've seen is use a resistor and a 3.3V zener diode to bring the voltage down.  This likely will cause you to lose bandwidth, so only try this if you are dealing with static digital outputs.

[jliu317]

Thanks.  Looks like this is not adjustable - possible idea for a future hardware update 😉

[crossrulz]

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@jliu317 wrote:

Thanks.  Looks like this is not adjustable - possible idea for a future hardware update 😉

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I wouldn't count on it.  Not many DIO cards out there will output different voltage levels.

The other benefit of using a buffer is the extra current.  Most DIO cards cannot put out much current (something like 2.4mA).  Buffers will allow for a lot more.  The buffers I typically use output up to 24mA.  But there are some that will do a lot more current.